This invention relates to a rack device for a getting machine employed in underground mining, and more particularly to a drum cutter mining machine having a drive coupled to a segmented rack extending along a face conveyor and supported on conveyor pan sections or side bracket portions thereof.
It is known in the art to provide a getting machine which is driven along a rack made up of individual rack sections. In one known form of a rack, each rack section has a length corresponding to the length of a side bracket portion or to the length of a conveyor pan section forming part of a conveyor. The individual rack sections are pivotally joined together and rigidly mounted upon the side bracket portions of the conveyor. In this form of construction, the rack is able to follow the course of movement by the face conveyor because of the sectional subdivision of the rack and its relation to the face conveyor or the side brackets of the face conveyor. Moreover, the rack is adaptable to the conveyor position characteristics in both the vertical and horizontal directions. However, it is impossible to equalize the relative displacements between the segmented rack longitudinally of the conveyor because of positional adaptation by the face conveyor or side bracket on the one hand and the position of the rack on the other hand without altering the pitch to the rack teeth at the joints between abutting rack segments.
It has also been proposed to provide a gear rack made up of pivotally-joined rack segments. The gear rack is slideably guided in the longitudinal direction of the face conveyor. However, the rack is mounted onto the face conveyor at one location. The gear rack is also fixed in the longitudinal direction with respect to the face conveyor or side bracket thereof. The rack is flexible with respect to the face conveyor or side bracket along the entire region outside the mounting location and during the shifting operation by the face conveyor, the rack undergoes relative movement of varying magnitude with respect to the face conveyor.